PBL3 Essay Example | Topics and Well Written Essays - 500 words

PBL3 - Essay Example There is no antibody production. There is destruction of the tissues involved and the organs fail to maintain their normal function. B. Cytopathic autoantibodies: This is the correct answer. Antibodies that are directed against one or more of the individuals own proteins are known as autoantibodies. Cytopathic autoantibodies cause degeneration of the cells they affect. In Graves disease, the autoantibodies are directed against the TSH receptor and mimics action of TSH, stimulating adenyl cyclase and increased release of thyroid hormones resulting in thyrotoxicosis. The antibody is known as long-acting thyroid stimulator or thyroid stimulating immunoglobulin. Another similar autoantibody called thyroid growth stimulating immunoglobulins cause growth of thyroid follicular epithelium. Similar T cell mediated autoantibody response causes infiltrative ophthalmopathy (Maitra, p.1172). C. Delayed type hypersensitivity: Inflammatory reactions initiated by mononuclear leukocytes are known as delayed hypersensitivity reactions. These reactions are mediated by T cells and monocytes/macrophages rather than by antibodies and are major mechanism of defense against various intracellular pathogens. They also occur in transplant rejection and tumor immunity. This reaction is not seen in Graves disease. Hence this is not the correct answer (Hinshaw, eMedicine). D. Immediate hypersensitivity: Immediate hypersensitivity is an allergic reaction provoked by re-exposure to a specific type of antigen referred to as an allergen. The plasma cells secrete IgE. The effects of this reaction are vasodilatation and smooth-muscle contraction. Hence this is not the correct answer. E. Immune complex disease: Combination of an epitope with an antibody is immune complex reaction. The effects are due to deposition of these complexes in various organs. This type of reaction is not seen in Graves disease. Hence this is not